Prime Minister Stephen Harper said that his government has "no real alternative" to the U.S. legal system in the Omar Khadr case Thursday, setting off a barrage of criticism from lawyers, opposition critics and human right activists.

"I think it's deplorable that he would say that there's nothing to be done," Khadr's U.S, military lawyer, Lt.-Cmdr. William Kuebler told CTV Newsnet. "This Canadian prime minister refuses to stand up to the Bush administration and protect the rights of a Canadian citizen.

"This is a disingenuous comment from the prime minister," Khadr's Canadian lawyer Dennis Edney told The Canadian Press.

"The prime minister, through his cabinet members, particularly Mr. (Peter) MacKay, have long said that they have been assured that Omar Khadr was being well treated, when in fact the Canadian government well knew that was not the case," he said.

The prime minister's comments come a day after explosive new documents suggest Canada was aware of the harsh treatment that Khadr was being subjected to in Guantanamo Bay at the hands of U.S. military interrogators.

But Harper, speaking Thursday in Tokyo, Japan following this week's G8 meetings, said Canada had little say in the situation and has no intention of interfering.

The Foreign Affairs documents released by Khadr's defence team this week show Khadr was visited in 2004 by Canadian officials. They found the then 17-year-old had been deprived of sleep for weeks in an attempt to make him more pliable for interrogation by U.S. agents.

"Every three hours he was moved to a different place. A different cell to disorient him, to make him weak," Edney said.

Alex Neve of Amnesty International Canada told CTV News that people "who have been through it have called it one of the most excruciating types of torture because it just goes on and on."

Harper has distanced his government from the documents. He said former prime minister Paul Martin's government was aware of how Khadr was being treated, but there was little that could have been done.

"The previous government took a whole range, all of the information into account when they made the decision on how to proceed with the Khadr case several years ago,'' he said.

Harper added that Canada: "frankly, has no real alternative'' to the U.S. legal process.

Harper criticized

Liberal foreign affairs critic Bob Rae, who was not part of the Paul Martin government, said on CTV Newsnet that "things got caught up" in the post-9/11 scramble to take direct action against terror suspects by governments.

But he says that time has passed and "it's extremely important for Canadians to take full responsibility for one of our own citizens and insist that he be brought home."

"Other countries have done the same and I can't, quite frankly, explain why Canada didn't do the same, but I think we should, and it's not too late to do that now," he added.

"I think it's time for Mr. Khadr to face justice in Canada."

Edney asked why Harper would criticize China's human rights record but ignore the situation in Guantanamo.

"It boggles my mind that this prime minister is prepared to criticize China over human rights and is prepared to lambaste Mexico for the way its criminal justice system is applied to a Canadian," he said.

"But when you have a young Canadian who is in Guantanamo Bay whom Canadian courts have said has been abused and tortured, our government remains silent."

Kuebler said the U.S. would probably have complied with a request from Harper to have Khadr transferred into Canadian custody -- but the request hasn't been made.

As a result, Kuebler said, any harsh treatment endured by Khadr is Canada's responsibility.

"The Canadian government has continued to hide behind assurances for the U.S. government that Omar Khadr is being treated humanely when it knew that . . . those assurances were false," he said.

The Toronto-born terror suspect is accused of throwing a grenade in 2002 in Afghanistan that killed a U.S. special forces soldier.

Khadr, 15 at the time, was captured and eventually sent to Guantanamo Bay, Cuba, where he has remained ever since.

The son of an alleged al Qaeda financier -- and the only Canadian being held in Gitmo -- Khadr is set to go to trial in October.

According to the reports released by Khadr's defence team, Canadian official Jim Ghould visited Khadr in 2004 and was briefed by U.S. military officials on Khadr's case.

One report says Khadr was moved every three hours for 21 days -- a technique known as the 'frequent flyer program' -- in an attempt to deprive him of sleep and weaken his ability to withstand interrogation.

And a U.S. Air Force report from February 2003 says Khadr wasn't allowed to receive mail from his family in Canada.

When he was finally given a letter from his grandmother, agents watched secretly as the young man broke down in tears.

The same report says Khadr was picked on by other inmates following his interview sessions with officials.

CTV's legal analyst Steven Skurka called the new revelations a "bombshell."

"We've been told repeatedly by the Canadian government he's been treated humanely and now it appears in the face of those statements the Canadian government knew otherwise," Skurka told Canada AM.

He added that the treatment described in the documents "could be called torture, it's certainly inhumane, it's certainly a story that really has to make Canadians wake up and shudder."

With files from The Canadian Press